# Watts to Kilowatt-Hours (kWh) Conversion Calculator

Convert watts to kilowatt-hours by entering power in watts and time in hours.

## Energy in Kilowatt-Hours:

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## How to Convert Watts to Kilowatt-Hours

A kilowatt-hour, expressed as kWh or kW·h, is a measure of energy that is equivalent to 1,000 watts of power for a 1-hour time period. Thus, to convert watts to kilowatt-hours, multiply the power in watts by the number of hours, then divide by 1,000.

### Watts to kWh Formula

Use the following formula to calculate energy in kilowatt-hours:

E_{(kWh)} = P_{(W)} × T_{(hrs)} / 1,000

The energy *E* in kilowatt-hours is equal to the power *P* consumed in watts times the time *T* in hours, divided by 1,000.

**For example:** let’s find the kWh of 1,500 watts for 2.5 hours.

E_{(kWh)} = 1,500 × 2.5 / 1,000

E_{(kWh)} = 3,750 Wh / 1,000

E_{(kWh)} = 3.75 kWh

Thus, the energy in kilowatt hours for a 1,500 power consumption over 2.5 hours is equal to 3.75 kilowatt-hours.

You can also use this formula to convert kilowatts to kilowatt-hours by not dividing by 1,000.

Electricity usage is often measured in watt-hours or kilowatt-hours, so if you can convert watts to kWh, then you can predict how much an electric appliance might cost, or how much energy is required to power it.

**For example:** let’s predict how much it costs to power a light bulb every hour. A 100-watt light bulb uses 100 watts of power. To convert the power in watts to kilowatt-hours, multiply 100 watts by 1 hour, then divide by 1,000 to find the energy usage in kWh.

E_{(kWh)} = 100 W × 1 hour / 1,000

E_{(kWh)} = 100 Wh / 1,000

E_{(kWh)} = 0.1 kWh

If electricity costs $0.12 per kWh, then a 100-watt light bulb will cost 1.2 cents per hour that it’s on.

Try our electricity cost calculator to estimate the cost of power usage on your monthly bill.

## Common Watts to Kilowatt-Hour Conversions

Power in Watts | Energy in Kilowatt-hours | Electricity Cost (at $0.12/kWh) |
---|---|---|

100 W | 0.1 kWh | $0.012 per hr |

200 W | 0.2 kWh | $0.024 per hr |

300 W | 0.3 kWh | $0.036 per hr |

400 W | 0.4 kWh | $0.048 per hr |

500 W | 0.5 kWh | $0.060 per hr |

600 W | 0.6 kWh | $0.072 per hr |

700 W | 0.7 kWh | $0.084 per hr |

800 W | 0.8 kWh | $0.096 per hr |

900 W | 0.9 kWh | $0.108 per hr |

1000 W | 1 kWh | $0.112 per hr |

To convert energy to watts, use our kWh to watts conversion calculator.